In general, distributed application is necessary and important in substation automation systems. Distributed applications, such as station-wide interlock application, distributed protection coordination, etc., are accomplished through data exchange among intelligent electronic devices (IED). Data exchange among IEDs, also being called horizontal communication, is based on peer-to-peer communication. Traditionally, distributed application is implemented by hardwire among relevant IEDs, and transfer of data through special input/output (I/O) cards to be inserted onto expansion slots in the IEDs. The traditional method has some advantages, including, for example, ease in debugging and tracing of signals during the engineering phase, and the clarity and ease for monitoring of the signal flows among IEDs, However, it also has the following drawbacks:
1) a number of I/O expansion slots and cards are needed;
2) numerous hardwire connection cables are laid around IEDs;
3) only binary signal can be communicated between IEDs.
In actual application, all of the above mentioned problems severely limit the scope and flexibility of distributed applications in substation.
After the introduction of IEC61850, digital substation which is based on this standard, and adopts Industrial Ethernet network as the fundamental communication bus across the whole application domain, has developed rapidly and become a trend in the substation automation system design. Generic Object Oriented Substation Event (GOOSE) based on IEC61850 international standard is one of the communication protocols, which provide fast and reliable data exchange among IEDs based on peer-to-peer communication on Industrial Ethernet network. Currently, GOOSE communication has been able to replace the traditional method completely through network communication mechanism. This kind of signal in GOOSE communication is also called “virtual signal”. Compared with hardwire connection, GOOSE communication network has more capacity and can transmit more diverse and complicated signals. So the scope of distributed application is more flexible for configuration and more reliable for communication. Furthermore, GOOSE communication network is easier for maintenance because no cable but only a few optical fibers or twisted-pairs are needed for connection among IEDs.
However, GOOSE network communication has disadvantages in actual application. As signal transmitted in the network is virtual and invisible, an efficient tool for signal testing and tracing is very important and needed. In fact, there is neither a method for GOOSE signal testing and monitoring, nor a method for checking the validity of the result of distributed application based on GOOSE. The logical connection relationship among the signals flowing among the IEDs is not explicit and there is no monitoring for the flow of the “virtual signal”. The performance of GOOSE signal depends on many factors which are determined dynamically by the network. In order to improve the reliability and to realize the advantages of GOOSE application, testing and monitoring for GOOSE application become very important in actual application. Nevertheless, the information of GOOSE signal logical connection relationship (which is called GOOSE signal logical connection topology), which indicates where the IED GOOSE signal comes from and where the IED GOOSE signal goes to, is a prerequisite for GOOSE testing and monitoring application. To generate GOOSE signal logical connection topology, a configured SCD or CID file which including GOOSE signal shall be imported. There are lots of methods concerning how to configure a SCD or CID file. For example, CN101431254A disclosed a method for configuring a GOOSE virtual terminal of an intelligent device in a digitalized substation, comprising the following steps: at least respectively defining the opening-inserting logic 1-i of the intelligent device as virtual terminals IN1-INi, and defining the opening-outgoing logic 1-j as virtual terminals OUT1-OUTj; expressing configuration of each intelligent device GOOSE in the form of connection in accordance with the principles of relay protection based on the intelligent device; respectively defining the terminal logic connection 1-k as LL1-LLk; arranging and re-expressing the configuration of the intelligent devices GOOSE in form of a list according to the logic connection based on virtual terminal logic connection; a GOOSE figuration list consists of the virtual terminal logic connection and the corresponding starting point and end point, wherein, the logic connection consists of two lists of the logic connection number LLk and the logic connection name.
The above mentioned method has finished the GOOSE signal configuration and got the SCD file which will be used and requisite for generating GOOSE signal logical connection topology. However, so far there is no method for generating GOOSE signal logical connection topology based on configured SCD file.
It is obviously that how to generate GOOSE signal logical connection topology is crucial for a better GOOSE application.